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Topic: Hotspot (geology)

	ScienceDaily: Hotspot (geology) (Site not responding. Last check: 2007-10-26)
		Hotspots were thought to be caused by a narrow stream of hot mantle convecting up from the mantle-core boundary called a mantle plume, the latest geological evidence is pointing to upper-mantle convection as a cause.
		Hotspot (geology) -- In geology, a hotspot is a location on the Earth's surface that has experienced active volcanism for a long period of time.
		Biodiversity hotspot -- A biodiversity hotspot is a biogeographic region that is both a significant reservoir of biodiversity and is threatened with destruction.
	www.sciencedaily.com /encyclopedia/Hotspot_(geology) (1567 words)

	Hotspot - TheBestLinks.com - DNA, Desert, Geology, Genetics, ...
		In geology, a hotspot is a location on the Earth's surface that has vulcanism for a long period of time.
		In meteorology, a hotspot is an area where the atmosphere is relatively hot.
		Examples of hotspots include the air over a desert or the region of Jupiter where the Galileo probe's atmospheric sub-probe descended.
	www.thebestlinks.com /Hotspot.html (299 words)

	Beyond the Plume Myth
		The hotspots associated with all of these events (except possibly for Siberia, which has left no track) are embedded in slower than average mantle and these presumably hot regions can be traced down to 200 to 300 km.
		The 'tail' part of the hotspot track may be a southerly propagating fracture tapping a shallow, enriched mantle of the Indian Ocean, or a huge shear zone, and reflects the stress field of the Indian Oceanic lithosphere, not its displacement history” (VII pp.
		The locations of large igneous provinces, hotspots and hotspot tracks are strongly controlled by lithospheric architecture and history: they are not placed randomly on the globe, indifferent to the surface geology; neither are large igneous provinces sudden chance events within the vastness of geological time (which plume theories typically allege)” (VII p.
	www.newgeology.us /presentation23.html (6760 words)

	blasts: University of Utah News Release: July 15, 2002
		The hotspot's history is marked not only by a slowdown in how often big eruptions occur, but by distinct changes in the compositions and temperatures of the magma, or molten rock, that erupted.
		Yellowstone hotspot caldera eruptions are believed to stem from molten basalt rising from depth, and then melting and mixing with the overlying granitic crust, which in turn erupts.
		A third possibility, which Nash believes is most likely, links the hotspot's behavior to two kinds of motion of the overlying rock: the southwest movement of the North American plate of Earth's crust, and the east-west stretching apart of the crust in the western United States during the past 17 million years.
	web.utah.edu /unews/releases/02/jul/hotspot.html (1439 words)

	Erosional Hotspots - USACE-FRF
		The objectives of the project are 1) to quantify the occurrence of hotspots, 2) to provide preliminary guidance to Corps engineers, and 3) to provide a classification system and database from which to identify candidate cases for further study on the causative processes.
		A large percentage of the hotspots experienced both chronic and post-storm erosion, demonstrating the importance of investigating hotspot behavior over short (weeks to months) and long (years to decades) time scales.
		The presence of outcropping geology (hardbottom, peat, etc) in the nearshore close to the hotspot was unknown.
	www.frf.usace.army.mil /hotspot/results.html (901 words)

	blasts: University of Utah News Release: July 15, 2002
		The hotspot's history is marked not only by a slowdown in how often big eruptions occur, but by distinct changes in the compositions and temperatures of the magma, or molten rock, that erupted.
		Yellowstone hotspot caldera eruptions are believed to stem from molten basalt rising from depth, and then melting and mixing with the overlying granitic crust, which in turn erupts.
		A third possibility, which Nash believes is most likely, links the hotspot's behavior to two kinds of motion of the overlying rock: the southwest movement of the North American plate of Earth's crust, and the east-west stretching apart of the crust in the western United States during the past 17 million years.
	www.utah.edu /unews/releases/02/jul/hotspot.html (1439 words)

	Hotspots \| World of Earth Science
		Hotspots are localized areas of volcanism and high heat flow within the earth's lithosphere above a mantle plume hot enough to melt portions of the overriding plate.
		Hotspots were thought to remain in a fixed position with respect to the earth's lower mantle.
		Hotspots were therefore used to define a unique, absolute reference frame to quantify the displacement of lithospheric plates.
	www.bookrags.com /research/hotspots-woes-01 (405 words)

	Geological Society of America - Penrose Conference - 1998
		Dennis Geist and Karen Harpp discussed the complexities that may have arisen from the conjunction of hotspot and ridge magmatism, including non-age-progressive volcanic activity, geographically widespread eruptions of similar age, a diversity of rock types atypical of ocean island volcanoes, and unusual spatial patterns displayed by isotope ratios and trace elements.
		This spatial pattern is attributable to the presence of a partial melt zone that extends to 150 km and is surrounded by a zone of melt-depleted upper mantle.
		The assumed plume origin of many "hotspots" has been questioned on the basis of observations such as lack of age-progressive volcanism and simultaneous eruption of volcanoes that are geographically widespread.
	www.geosociety.org /penrose/98pcrpt2.htm (3129 words)

	WHOI : Oceanus : Hitting the Hotspots
		Hotspots are relatively small regions on the earth where unusually hot rocks rise from deep inside the mantle layer.
		A theoretical geodynamic model shows that a narrow hotspot "root," such as the one recently discovered beneath Iceland, would generate a vigorous source of heat (light colors) and produce a huge volume of magma that would migrate laterally along and across the ridge axes hundreds of kilometers away from the hotspot source.
		While hotspots such as Iceland and Hawaii may have their origin deep in the mantle, others may simply reflect large concentrations of unusual chemical properties in the earth’s shallow mantle.
	www.whoi.edu /oceanus/viewArticle.do?id=2396 (1567 words)

	Galapagos Scenery geology - hotspot model
		To explain the origin of mid-oceanic island chains such as the Galapagos Islands, geologists devised the so-called "hotspot" theory.
		As the oceanic plate moves over hotspot an new island is created and the old one is eroded by wave and weather action.
		Other evidence for the hotspot model is the relative ages of islands: youngest in the west, the oldest to the east.
	www.junglephotos.com /galapagos/gscenery/geology/hotspot.shtml (175 words)

	Hotspot stability and mobility (Site not responding. Last check: 2007-10-26)
		Proponents of hotspot fixity assume that the hotspot sources are all fixed to one another in a “hotspot reference frame” and that the lithospheric plates are moving around on top of this reference frame.
		If this reference frame exists, then all the hotspots should be fixed to one another, and if we reconstruct the plates correctly, then the past position of all of these hotspots, relative to one another, should not vary as one goes back in time.
		Dated hotspot tracks on one plate, that have been used to derive a set of rotations describing the relative motion of the hotspot reference frame with respect to this plate.
	www.mantleplumes.org /HawaiiFocusGroup/Stock_abs.html (1435 words)

	Bermuda's Caves
		iodiversity hotspots are defined as relatively small areas with exceptional concentrations of endemic species.
		Bermuda's marine caves readily qualify as a biodiversity hotspot of global significance due to their remarkably rich and diverse community of cave-limited animals.
		Geology and origin of the caves of Bermuda.
	www.tamug.edu /cavebiology/BeCKIS/hotspot.html (1865 words)

	Biodiversity Hotspots - California Floristic Province - Unique and Threated Biodiversity
		Of nearly 3,500 species of vascular plants in the hotspot, more than 2,120 (61 percent) are found nowhere else in the world.
		Four subregions within the hotspot are centers of exceptionally high plant diversity: the Sierra Nevada, the Transverse Ranges in southern California, the Klamath-Siskiyou region in the coastal mountain ranges of California and Oregon, and the Coast Ranges.
		The hotspot is also home to two spectacular endemic tree species, the giant sequoia (Sequoiadendron giganteum) and the coastal redwood (Sequoia sempervirens).
	www.conservation.org /xp/Hotspots/california_floristic/biodiversity.xml (1022 words)

	hotspot \| English \| Dictionary & Translation by Babylon
		HotSpot, first released April 27, 1999, was originally developed by Animorphic, a small startup company (also responsible for Strongtalk).
		Hotspot (geology), a location that has experienced active volcanism for a long time
		Hotspot (stage lighting) The center of a beam of light from a stage lighting instrument that appears brighter than the surrounding light.
	info.babylon.com /onlinebox.cgi?rt=ol&cid=CD776&term=hotspot&tl=English&uil=English&tid=AffToolbar (376 words)

	Erosional Hotspots - USACE-FRF
		The literature provides many examples of hotspots (see Kraus and Galgano, 2001; Dean et al., 1999) but the scope of the problem in both number of hotspot occurrences around the US and their causes remains speculative.
		The ability to mitigate these erosional hotspots requires effective low-cost monitoring techniques and simple diagnostic methods that can link underlying geology, response time histories, changes in beach and nearshore morphology, and other non-traditional factors to the knowledge and information developed during project design and gathered by conventional monitoring.
		This hotspot knowledgebase will serve several purposes including: 1)quantify the occurrence of hotspots, 2) provide preliminary guidance to Corps engineers based on experience gained from known hotspots, and 3) provide a classification system and database from which to identify candidate cases for further study on the causative processes.
	frf.usace.army.mil /hotspot/index.html (310 words)

	Hotspot (geology) - guideofcasinos.com (Site not responding. Last check: 2007-10-26)
		Tuzo Wilson came up with the idea in 1963 that volcanic chains like the Hawaiian Islands result from the slow movement of a tectonic plate across a "fixed" hot spot deep beneath the surface of the planet.
		Originally thought to be caused by a narrow stream of hot mantle convecting up from the mantle-core boundary called a mantle plume [1], the latest geological evidence is pointing to upper-mantle convection as a cause [2][3].
		Geologists have identified some 40-50 such hotspots around the globe, with Hawaii, RÃ©union, Yellowstone, Galapagos, and Iceland overlying the most currently active.
	www.guideofcasinos.com /Hotspot_%28geology%29.html (134 words)

	May GEOLOGY media highlights
		The origin of the hotspot is controversial, and the volcanism, rifting, and uplift have commonly been attributed to one or more starting mantle plumes in the mantle beneath this area.
		This Geology paper documents evidence of uplift, tilting, and convergence on the Bering Sea coast of Kamchatka, contradicting the single-plate model.
		Using the average nitrogen/carbon ratio (N/C) of sedimentary organic matter, coal, and volcanic/metamorphic gases, existing models of the carbon cycle have been used to calculate the fluxes of nitrogen to and from the atmosphere via the weathering, burial, and metamorphic/volcanic decomposition of organic matter.
	www.eurekalert.org /pub_releases/2006-04/gsoa-mgm042606.php (3445 words)

	Geo112 Volcanos lecture
		These volcanos mark the trace of a plate as it drifts steadily over the hotspot, which is fixed (or nearly so) in the mantle beneath the plate.
		As each volcano drifted to the northwest with the Pacific plate, it moved away from the mantle hotspot and became extinct.
		Flood basalts are voluminous outpourings of sheets of basaltic magmas that are believed to originate when the head of a mantle hotspot (or plume) first arrives beneath the base of a plate.
	www.geology.wisc.edu /courses/g112/volcano.html (1977 words)

	Yellowstone National Park, Part 1
		Yellowstone is a region that is defined by its geology.
		Unlike other hotspots, which erupt basaltic lava (which is fluid-like and usually flows out as lava), the magma under Yellowstone is rich in silica, and erupts as rhyolite.
		Yellowstone’s history and all the activity we see at Yellowstone, from the geysers and hot springs to the earthquakes are the result of this hotspot.
	www.suite101.com /article.cfm/everyday_geology/86400 (524 words)

	NOAA Ocean Explorer: Exploring Alaska's Seamounts
		A hotspot is a point of frequent volcanic activity that persists over millions of years.
		As one seamount is carried away from the hotspot another forms in its place, so the older the seamounts are, the farther they have been carried by the plate.
		This is occurring today in Hawaii (another example of a hotspot) as volcanic activity on the island of Hawaii is slowly being replaced by activity on nearby Loihi seamount.
	oceanexplorer.noaa.gov /explorations/02alaska/background/geology/geology.html (900 words)

	Biodiversity Hotspots - Western Ghats & Sri Lanka - Overview
		Population levels are also applying increased stress on the fringes of protected areas where many farms, loggers, and poachers use the resources illegally.
		Due in part to the varying effect of the yearly monsoons and the high mountain regions, this hotspot is home to a rich endemic assemblage of plants, reptiles, and amphibians.
		The Western Ghats of southwestern India and the highlands of southwestern Sri Lanka, separated by 400 kilometers, are strikingly similar in their geology, climate and evolutionary history.
	www.biodiversityhotspots.org /xp/Hotspots/ghats (591 words)

	Yellowstone Super Volcano
		A hotspot is simply a location at the earths crust where magma from the mantle releases heat and in turn shapes the crust.
		More importantly you can see the past history of the hotspot, as an island chain, throughout the movement of the plate first towards the north and then west.
		The hotspot is more difficult to track than the Hawaiian Island chain but by using various dating techniques and carefully analyzing the surrounding rocks geologists have been able to identify several such hotspot eruptions over a period of approximately 17 million years.
	geology.fullerton.edu /whenderson/Fal201L2005/Yellowstone/Yellowstone.htm (632 words)

	Bob Smith: Research (Site not responding. Last check: 2007-10-26)
		Lithospheric deformation on the scale of Yellowstone's hotspot is associated with large-scale mantle processes generally have an observable response in river drainage systems.
		The highest elevations are associated with the topographic divides at 1,500 to 2,000 m in elevation and the bordering topographic shoulders extend southwestward from Yellowstone for 400 km wrapping around the SRP in the characteristic parabolic pattern.
		An interpretation of the geoid is that is considered a representation of the degree of isostatic compensation and is an equipotential surface reflecting an amalgam of topographic relief and density variation.
	www.mines.utah.edu /~rbsmith/RESEARCH/YellowstoneHotspot.html (3739 words)

	USACE-FRF Hotspot Questionnaire
		For the purposes of this survey, hotspots are defined as areas that persistently have elevated erosion relative to the surrounding beach, including locations that erode more during storms (short-term only) and/or long-term (annual-decadal).
		You may find it useful to have site maps of the hotspot sites and a ruler as some of the questions ask that you provide distances.
		Please fill in and submit a separate survey for each hotspot location, including all project beaches (renourished and non-renourished) for which information is available.
	www.vims.edu /physical/hotspot/survey.html (432 words)

	NPS: Nature & Science» Geology Resources Division (Site not responding. Last check: 2007-10-26)
		This shows that the hotspot isn't moving, but the plate definitely is. The islands on the Pacific Plate grow progressively older as you move from east to west.
		The park's geology may be described in regional or state geology texts.
		Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.
	www2.nature.nps.gov /geology/parks/npsa/index.cfm (1253 words)

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